perf: Add foreign key indexes to tables

db-service/lib/SQLService.js

@@ -294,8 +294,39 @@ class SQLService extends DatabaseService {
       DEBUG?.(query, data)
       const ps = await this.prepare(query)
       const exec = this.hasResults(query) ? d => ps.all(d) : d => ps.run(d)
-      if (Array.isArray(data) && Array.isArray(data[0])) return await Promise.all(data.map(exec))
-      else return exec(data)
+      let ret
+      if (Array.isArray(data) && Array.isArray(data[0])) ret = await Promise.all(data.map(exec))
+      else ret = await exec(data)
+
+      // Leverage modeling structure to create table indexes
+      if (this.model && /^\s*CREATE TABLE/i.test(query)) {
+        // Extracts the name from the incoming SQL statment
+        const name = query.match(/^CREATE TABLE ("[^"]+"|[^\s(]+)/im)[1]
+        // Replaces all '_' with '.' from left to right
+        const split = name.split('_')
+        const options = split.map((_, i) => split.slice(0, i + 1).join('.') + '.' + split.slice(i + 1).join('_'))
+        // Finds the first match inside the model
+        const target = options.find(n => this.model.definitions[n])
+
+        // if target definition is found create foreign key indexes
+        if (target) {
+          // Create indexes for foreign key columns
+          const cqn2sql = new this.constructor.CQN2SQL(this)
+          const indexes = {}
+          const entity = this.model.definitions[target]
+          for (const e in entity.elements) {
+            const element = entity.elements[e]
+            const assoc = element._foreignKey4
+            if (!assoc || element.virtual) continue
+            (indexes[assoc] ??= []).push(cqn2sql.quote(element.name))
+          }
+          for (const assocName in indexes) {
+            await this.exec(`CREATE INDEX ${cqn2sql.quote(name + '_' + assocName)} on ${cqn2sql.quote(name)} (${indexes[assocName]})`)
+          }
+        }
+      }
+
+      return ret
     } else return next()
   }
 

test/scenarios/bookshop/read.test.js

@@ -55,10 +55,10 @@ describe('Bookshop - Read', () => {
     expect(res.data.value.length).to.be.eq(4) // As there are two books which have the same author
     expect(
       res.data.value.every(
-      item =>
-        'author' in item &&
-        'ID' in item.author && // foreign key is renamed to element name in target
-        !('author_ID' in item.author),
+        item =>
+          'author' in item &&
+          'ID' in item.author && // foreign key is renamed to element name in target
+          !('author_ID' in item.author),
       ),
     ).to.be.true
   })
@@ -355,18 +355,18 @@ describe('Bookshop - Read', () => {
   })
 
   it('allows filtering with between operator', async () => {
-    const query = SELECT.from('sap.capire.bookshop.Books', ['ID', 'stock']).where ({ stock: { between: 0, and: 100 } })
+    const query = SELECT.from('sap.capire.bookshop.Books', ['ID', 'stock']).where({ stock: { between: 0, and: 100 } })
 
-    return expect((await query).every(row => row.stock >=0 && row.stock <=100)).to.be.true
+    return expect((await query).every(row => row.stock >= 0 && row.stock <= 100)).to.be.true
   })
 
   it('allows various mechanisms for expressing "not in"', async () => {
     const results = await cds.db.run([
-      SELECT.from('sap.capire.bookshop.Books', ['ID']).where({ ID: { 'not in': [201, 251] } }),
-      SELECT.from('sap.capire.bookshop.Books', ['ID']).where({ ID: { not: { in: [201, 251] } } }),
-      SELECT.from('sap.capire.bookshop.Books', ['ID']).where('ID not in', [201, 251])
+      SELECT.from('sap.capire.bookshop.Books', ['ID']).where({ ID: { 'not in': [201, 251] } }).orderBy('ID'),
+      SELECT.from('sap.capire.bookshop.Books', ['ID']).where({ ID: { not: { in: [201, 251] } } }).orderBy('ID'),
+      SELECT.from('sap.capire.bookshop.Books', ['ID']).where('ID not in', [201, 251]).orderBy('ID')
     ])
 
-    for (const row of results) expect(row).to.deep.eq([{ID: 207},{ID: 252},{ID: 271}])
+    for (const result of results) expect(result).to.deep.eq([{ ID: 207 }, { ID: 252 }, { ID: 271 }])
   })
 })